Introduction. Francisella tularensis is a gram-negative facultative intracellular pathogen that causes lethal disease in humans, and is a potential biowarfare agent. Surprisingly little is known about the overall protein physiology of this bacterium, and only a handful of potential vaccine candidates are identified at the molecular level. Recent efforts were undertaken to sequence the genomes of the attenuated vaccine strain F. tularensis subsp. holarctica LVS and the virulent F. tularensis subsp. tularensis strain Schu4. The completed genome sequences of these two organisms enable the application of high throughput genomic and proteomic techniques for the identification of vaccine antigens. Specifically, proteomic techniques including array technologies developed implemented to identify dominant antigens of other intracellular pathogens will be applied to F. tularensis. These antigen screens will provide a defined set of potential vaccine candidates that will be evaluated in conjunction with adjuvant formulations to assess protective efficacy and the nature of the immune response elicited. The overall goal of this project is to develop three to four vaccine formulations that are suitable for scale-up production under GMP and transition to clinical studies. Project interactions: This project will be closely integrated with other projects and with Core Facilities described in this proposal. The Pis of this project is Dr. Belisle. Dr. Petersen and Bosio will serve as Co- Pis, and Dr. Feigner will serve as the PI of a sub-contract to the University of California, Irvine. We will work closely with the Genomics/Proteomics Core to apply bioinformatics to the identification of Schu4 ORFs and the molecular identification of proteins by mass spectrometry. We will also work closely with the Animal Core in the implementation of the murine model for F. tularensis infection and will transfer protocols for vaccine testing to this core. As successful vaccine candidates and formulations are identified they will be transferred to the PDM Core for production under GMP conditions. The basic approaches implemented in this project will be applicable to the development of vaccines against other select agents. In particular there will be close interaction with groups that are targeting the development of vaccines to Coxiella spp (Projects II.E.2, II.E.3, and II.E.4.) and the elucidation of the immune response to Burkholderia spp. (Project M.A.4.). There will also be close interaction with Drs. Kedl and Blair (Project II.C.6) on the use of liposomes as a vehicle for the delivery of vaccine antigens